Related Articles

You may want to save vinegar for salad dressing. While this acidic liquid is sometimes recommended as a plant fungicide, spraying vinegar directly on plants is a bad idea since you may kill or damage foliage. While some homemade fungicide recipes include a little vinegar, no scientific studies to date support the idea that vinegar kills plant fungi.

Herbicide

Vinegar is an effective herbicide, and a 5 percent vinegar spray will kill weeds. But, according to experts at the Lady Bird Johnson Wildflower Center, vinegar is a poor choice to control weeds since it takes out not just weeds but every plant with which it comes in contact. If you spray pure vinegar on plant fungi, you may end up with dead plants, too.

Homemade Fungicide Recipes

Vinegar is often an ingredient in recipes for homemade fungicide spray. Huntington Botanical Gardens recommends a spray made with 1 gallon water and 1 tablespoon each of baking soda, horticultural oil and vinegar for treating black spot and powdery mildew, as long as the temperature is under 80 degrees Fahrenheit. However, according to University of Kentucky experts, few organic remedies for treating fungus, including apple cider vinegar, have been studied with "adequate checks."

Alternatives

If you decide against using vinegar to control plant fungi, other nontoxic options can control powdery mildew, black spot and rust. According to Fine Gardening, you can eliminate these fungal diseases by dissolving two aspirins in a quart of water and using it as a foliar spray.

About the Author

From Alaska to California, from France's Basque Country to Mexico's Pacific Coast, Teo Spengler has dug the soil, planted seeds and helped trees, flowers and veggies thrive. World traveler, professional writer and consummate gardener, Spengler earned a BA from U.C. Santa Cruz, a law degree from Berkeley's Boalt Hall, and an MA and MFA from San Francisco State. She currently divides her life between San Francisco and southwestern France.